BAGHDAD -- Almost four years after his accidental rise to power, Prime Minister Nouri al-Maliki is trying to retain his job without the allies who made him Iraq's ruler the first time around.

Maliki remains the most powerful Shiite political leader in the country. But he finds himself politically isolated and regionally estranged, with his foremost selling point, a fragile security on the streets of Iraq, crumbling after a series of attacks on government buildings and iconic Baghdad hotels that has killed more than 400 people since August.

With parliamentary elections scheduled for March 7, the question of whether Maliki can hold on as prime minister will determine what kind of country the U.S. military leaves behind as it significantly reduces its presence this spring.

Maliki remains an inscrutable figure: He began as an obscure politician viewed by many as sectarian, has lately cast himself as a nationalist and has spawned fears of a return to the kind of authoritarianism that prevailed before the 2003 U.S.-led invasion. Another Maliki term could shepherd Iraq's democratic experiment forward or could expose it as an aberration amid a much longer history of dictatorial rule.

His allies say there is no other option. It is Maliki, they say, who has brought stability to a country that has had five changes of government in six years.

"Maliki has managed to stay in power not because he is strong or weak but because of the absence of an alternative," said Sami al-Askari, an independent Shiite politician close to the prime minister.

But even allies say Maliki's effort to transform his image from a Shiite Islamist to an Iraqi nationalist may ultimately defeat him. Having distanced himself from sect- and ethnicity-based coalitions, he has won fewer friends than enemies. Other Shiite Islamists worry that he has opened the door to rival powers: Kurds are angered by his challenges to their territorial claims; he failed to woo prominent Sunni Arabs into his political bloc; and Iran, which aided Maliki's rise to power, feels it has lost control over him.

"He feels isolated politically and regionally, but he thinks that he is accepted by the nation," said Ezzat Shahbandar, an independent Shiite politician who has joined Maliki's coalition.

The legitimacy of the election is the biggest worry for the United States. Concern has grown after a decision by an Iraqi government commission to disqualify more than 500 candidates purportedly adhering to the ideals of Saddam Hussein's Baath Party, the most prominent of whom are Sunni Arabs. A ruling on Wednesday by a panel of judges might allow the banned candidates to run, but the initial disqualification has already alienated Sunnis, who boycotted the 2005 elections.

Maliki, who has long feared that the Baathists could rise again, is in a precarious position. If he pushes to reinstate the candidates, he risks alienating voters who fear the return of the Baathists; if he does not, he loses credibility among Sunni Arabs, whom he has tried hard to woo.

The evolution of a leader

Maliki took office in 2006 as a compromise candidate. As the choice to succeed Prime Minister Ibrahim al-Jafari, he was picked primarily because Shiites were torn between the Islamic Supreme Council of Iraq, the once-dominant Shiite group that was created in Iran and spent years in exile there, and the Sadrists, a grass-roots party that represents the Shiite poor.

Iran, the Shiite parties and their Kurdish allies thought they could control Maliki, a member of the smaller Dawa party. But two years into his term, he stunned his supporters and crossed sectarian lines.